L92 setup for a LQ4
02-01-2007, 02:03 PM
#31
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Okay so let me get this straight, the L92 heads will bolt up to an Lq4 shortblock with no problems, the valves are not too large? You just need the corresponding intake manifold and gasket correct?
02-01-2007, 03:41 PM
#32
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KB,
There is the issue of throttle body compatibility. My LQ4 has a cable-actuated throttle with three mounting holes. This is incompatible with the 4 bolt 90 mm design on the new L92 manifold. Also, there is the issue of the injector connector and electrical interface that I raised earlier. What kind of vehicle do you have? Especially, is it a cable-operated throttle or is it electronic with integral idle air control and cruise control operation. All of this can be dealt with, but it's probably not going to be fully plug and play. Also, the new L92 equipped vehicles have dual electric cooling fans and the air intake duct that runs from the air cleaner to the TB will be set up differently from the LQ4/LQ9 80 or 85 mm setup.
My whole point back in post 19 https://www.performancetrucks.net/fo...6&postcount=19 is that if the new L92 manifold doesn't flow reasonably better than the LQ4/LQ9 and if the injectors aren't compatible, etc. then the whole exercise of going to the L92 head may not be very beneficial. You might be better off to get a decent pair of CNC ported cathedral style heads instead and save all the drama of multiple modifications.
Richard pointed out some time ago that it would be great if FAST made a truck specific intake. This FAST concept would be easier than adapting the L92 in many cases.
Steve
There is the issue of throttle body compatibility. My LQ4 has a cable-actuated throttle with three mounting holes. This is incompatible with the 4 bolt 90 mm design on the new L92 manifold. Also, there is the issue of the injector connector and electrical interface that I raised earlier. What kind of vehicle do you have? Especially, is it a cable-operated throttle or is it electronic with integral idle air control and cruise control operation. All of this can be dealt with, but it's probably not going to be fully plug and play. Also, the new L92 equipped vehicles have dual electric cooling fans and the air intake duct that runs from the air cleaner to the TB will be set up differently from the LQ4/LQ9 80 or 85 mm setup.
My whole point back in post 19 https://www.performancetrucks.net/fo...6&postcount=19 is that if the new L92 manifold doesn't flow reasonably better than the LQ4/LQ9 and if the injectors aren't compatible, etc. then the whole exercise of going to the L92 head may not be very beneficial. You might be better off to get a decent pair of CNC ported cathedral style heads instead and save all the drama of multiple modifications.
Richard pointed out some time ago that it would be great if FAST made a truck specific intake. This FAST concept would be easier than adapting the L92 in many cases.
Steve
Last edited by Steve Bryant; 02-01-2007 at 03:52 PM.
02-01-2007, 04:22 PM
#33
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Wow, thanks for the info Steve. I have a 2006 Silverado with drive by wire and electric fans, but I still would not want to mess with the airbox location and anything else simply because i can't afford to do so lol. I'll just stick to the proven combos. 
Thanks again.
Thanks again.
02-01-2007, 07:33 PM
#34
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you can get the l76 intake package with throttle body(electric) from SDPC. Then you can go ahead and get a nick william 90mm TB cable style if that's what came stock. The injectors and fuel rails will have to be modified. Why dont you use the l76 car intake with the l92 heads?
02-01-2007, 10:46 PM
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Originally Posted by silverbrick
you can get the l76 intake package with throttle body(electric) from SDPC. Then you can go ahead and get a nick william 90mm TB cable style if that's what came stock. The injectors and fuel rails will have to be modified. Why dont you use the l76 car intake with the l92 heads?
Another way to look at this is if you put a car intake on a truck application, how will you get the intake duct installed to the inlet side of the TB without running into the fan/shroud? The water pumps are made differently for the same/similar reasons.
Steve
02-01-2007, 11:25 PM
#38
I didn't see this article mentioned yet. Richard, this is some interestig data to compare to what your shop ends up with since they list all the flow data they got.
gmhighperformance
They swapped the stock LS2 heads for L92 and then went a little further and compared the GMPP carb style intake to the L76 car intake which is offered here now. It even lists the GM part numbers.
In any event they got some good numbers. Personally I like the L92 heads with the L76 intake that comes with a throttle body, rails and injectors (39lb) for about $500. Pretty good bang for the buck when paired with the L92 heads.
gmhighperformance
They swapped the stock LS2 heads for L92 and then went a little further and compared the GMPP carb style intake to the L76 car intake which is offered here now. It even lists the GM part numbers.
In any event they got some good numbers. Personally I like the L92 heads with the L76 intake that comes with a throttle body, rails and injectors (39lb) for about $500. Pretty good bang for the buck when paired with the L92 heads.
02-01-2007, 11:32 PM
#39
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Originally Posted by meatwad
In any event they got some good numbers. Personally I like the L92 heads with the L76 intake that comes with a throttle body, rails and injectors (39lb) for about $500. Pretty good bang for the buck when paired with the L92 heads.
You have any ideas? PM me so no thread jack anyone
02-02-2007, 12:23 AM
#40
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I read the article in GMHTP and it looked pretty nice. It shows the potential of the L92 heads in stock form. As mentioned above fitting the injector rails could pose some small problems, but I'm certain this will be easily resolved.
I've been crunching on the L92 CNC program off and on for the last 3 months and I'm beginning to see the light at the end of the tunnel. I should have a Stage 2 program ready in a couple of weeks. Intake valves are delayed until the end of Febuary. In the meantime we're using REV custom valves. I'll post some flow data when the program is finalized and hopefully some dyno data very soon after.
Richard
I've been crunching on the L92 CNC program off and on for the last 3 months and I'm beginning to see the light at the end of the tunnel. I should have a Stage 2 program ready in a couple of weeks. Intake valves are delayed until the end of Febuary. In the meantime we're using REV custom valves. I'll post some flow data when the program is finalized and hopefully some dyno data very soon after.
Richard